Safety device for aircraft



Oct. 5, 1937. w. E. METHVIN SAFETY DEVICE FOR AIRCRAFT Filed March 6, 1934 2 Sheets-Sheet l Oct. 5, 1937. w. E. METHVIN 2,094,955

SAFETY DEVICE FOR AICRAFT Filed March 6, 1934 2 sheets-sheet 2 INVENTOR L c5,

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Patented Ochs, 1937 UNITED STATES PATENT OFFICE SAFETY DEVICE FOB. AIRCRAFT Wilbur E. Methvin, Lawrenceburg, Tenn.

Application March 6, 1934, Serial No. 714,310

Claims.

My invention relates to aircraft and more particularly to an improved safety device for airplanes.

I-Ieretofore, it has been suggested to equip air- 5 planes with safetyvdevices, in the form of an auxiliar'y propeller adapted when released for rotation, to retard or check the descent `of an airplane, in the event that the airplane becomes disabled so that sustained flight can not be mainl0 tained. In the prior art devices, the rotating' member is sometimes mounted for free rotation and it has also been proposed to drive the inember directly, by connecting it to the aircraft prime mover or an auxiliary motor. If the rotatable propeller is mounted exterior of the wing surfaces and remains in this position during the normal operation of the aircraft, considerable drag is created, which materially reduces the eiciency of the airplane. To overcome this objection, it has been suggested to provide the upper wing with a recess adapted to receive the auxiliary propeller during normal flight and means are provided whereby the propeller may be moved into the operative position.

'I'he last mentioned arrangement, while reducing the drag, is open to the objection that it is too complicated, since it requires the operation of a series of mechanisms before the safety device will function. It will be appreciated that any device of this character, designed to increase the factor of safety for aircraft, generally, must of necessity be constructed and arranged so that it will operate automatically, instantaneously, land with. minimum movement of parts, otherwise 35 it fails to meet the inherent requirements for a practical, operative, safety device.

My invention aims to provide for the deficiencies of the prior art arrangements and at the same time overcome certain objections found 40 therein. The improved safety device, of the present invention, comprises generally a construction wherein the upper wing of the aircraft is adapted to be released for free rotation about a central supporting shaft, in event that the airplane becomes damaged or disabled. The rotatable wing is designed to function as a conventional airfoil during normal flight and operates toprevent sudden descent of the airplane, when it is released for free rotation.

An object of my invention is to provide an improved safety device for aircraft wherein one of the normally stationary airfoils is adapted for free rotation.

Another object of my invention is. to provide an aircraft having an airfoil adapted to function as out the aid of any mechanical drive means. I0

A further object of my invention is to provide a safety device for aircraft, having an improved wing structure whereby the freely rotatable member rotates in a predetermined direction.

A still further object of my invention is to rpro- 15 vide a safety device for aircraft which is strong and sturdy in construction, consisting of but few parts and one that is not liable to get out of order even after long and continued use.

With these and other objects in view, which may be incident to my improvements, the invention consists in the parts and combinations to be hereinafter set forth and claimed, with the un-l derstanding that the several necessary elements, comprising my invention, may be varied in construction, proportions and arrangement, without departing from the spirit and scope 0f the appended claims.

In order to Amake my invention more clearly understood, I have shown in the accompanying 30 drawings means for carrying the same into practical eifect, without limiting-the improvements in their useful applications to the particular constructions, which for-the purpose of explanation, have been made the subject of illustration.

In the drawings:

' Figure 1 is a plan view-of an airplane provided with my improved safety device.

Fig. 2 is a front elevational view of the arrangement shown in Figure 1. 40

Fig. 3 is a Side elevational view of the aircraft shown in Figure 1.

Fig. `4 is a sectional view along line 4-4 of Figure 2, showing the mounting for the rotatable Wing, p 45 Fig. 5 is a sectional View along line 5-5 of Figure 2.

Fig. 6 is a sectional view along line 6-6 of Fig- -ure 2; and

Fig. '7 is a modification of the releasing device shown in Figure 4.

Referring to the drawings and more particularly to Figures 1 to 3, there is shown an airplane comprising a fuselage I, provided with an empennage, designatedgenerally by numeral 2. Ex- 5b tending outwardly fromthe sidesof the fuse aretwoairfoilslandlformingaxedwingfor theaircraft,andabovethiswlngthereismount edawingicomprlsing airi'oilportionsland 1. Thetopwingiisrotatablymounteduponthe fuselage I through the medium of a suitable hanger comprising asuppOrt member l provided WithhilbDOrtlOnslandll. Theairfdlslandun tilted upwardly from adihedmi angie and they are supported in`thissposition by means of -struts il and I2,thestn1tsbeingattachedtothe underside or the wing and terminating in the hub A portion i.

Itwillbenotedthatthewingmemberiis mounted 'forwardlyof the lower xed wing and thattheleadingedge Ilofportioniislowerthan the leading edge -Il of portion 1; 'Ihe purpose of this arrangement is to insure positive rotation' of thevwing 'as' soon a's-.it is released for free rotation about its supporting member I, as will be described more fully hereinafter.

- Referring toFlgure 3, I have shown one form of mounting and release mechanism, whereby the upperwingiisper'mittedtofreelyrotatebout its support. The wing is securely attached to hub portion Il of support'member I by suitable fastening means I5, adapted to pass through the flanged portion It of the hub anc' the lower end Ao`fthetubularsupport8Isfol-metiwithailanged portion I`l,adaptedtorestuponabearingplate il whichseats in areeess II formed in the fuselage. A suitable cover plate 2l is provided for thewrposeofpreventingpassage ofdirtorother,

foreign matter to the bearing surfaces. Within the tubular member I, there is mounted a stationary shaft 2| embedded in the fuselage and formed with ball races 22 and 2l `near the topv and bottom thereof, the races being adapted to accommodate a plurality of ball bearings 24 and 2i. j v

Itwillbeseenthatwhenwinglrotates,it turns member l with it and that the upward and downward thrusts exerted upon the member aretaken upbytheball bearlngsat'thetopand f 'bottom of the stationary shaft. In order to lock member [against rotation, the lower hub portionlisrecessedasatllandadaptedtoreceive the end of a sprlngpressed plunger 2l supportedin a suitable housing 28 through which it exftends, the plunger passing through a spring 2l and terminating i'nahand grip member 30. BetWeentheendoithehousingIIandgrlpmember 2l, there is provided a rtojection or key Il v arranged to cooperate-with a stop l2 and `hold thro plunger in Vthe position. A cable 33 attachedto grip maybeused forremotecontrol of the releasing device.

-In the operation of the device, wing l is -nor- I nally stationary and assinnes the position shown inldsurel. Iftheaircraftshouldbecamedamvaged or disabled, the end of plunger 21 is released the air in event thatthe airplane tends to fait` vertically. When the top wing rotates, considerable lift is exerted and the airplane lspermitted to descend gently` and without any danger of overturning or spinning.

nernngwmguressanaetmubenod 'accesos 1 that airfoil portion 6 is tilted downwardly so that the leading edge i3 is below the horizontal, the 'section as shown being provided with a blunt leading edge and a thin trailing edge 34. Airfoil l is also tilted, but in the opposite direction to portion I, with its leading edge Il above the horizontai, the section being formed with a double camber having a blunt trailing edge 3l. 'nie construction and arrangement of the airfoil sections forming the rotatable wing 5, is designed to make one side of the wing more readily stallable than the other side. At large angles of attack, one side of the wing will have aj larger drag than the other side, whereby spinning of the wing is effected Iwhen it is released for free rotanon. l

While the arrangement disclosed herein has been referred to as a safety device adaptedto y'be used in `event that the airplane becomes disabled, the invention in its* broadest aspect comprehends normal use in connection with an airplane which is not disabled. That is, the rotatable wing maybe released for free rotation before the plane leaves the ground, in order to obtain the benefit ofthe increasedL lift, produced by the novel design of the rotating wing structure. After the aircraft has reached the desired altitude,-the wing may be braked'and held in the position shown vin Figurel. It has been found, as a result of extensive tests, that when the airplane is levelled oil', the rotating wing automatically assumes a position with its leading edge parallel to the leading edge of the ilxed wing. It is possible, therefore, to use the device without any locking or release means. As long as the airplane continues in substantially horizontal flight, the wing remains stationary, however, if the angularity of the plane is changed, the wing .begins to rotate.

For the purpose of locking the rotatable wing in a xed position, if it is found desirable to do so, Ihave provideda raking arrangement shown in Figure 7. The hu portion l' is extended to accommodate the lower ends of the struts Il and I2 and the lower portion thereof is adapted to receive a band It which is arranged to be clamped into frlctionnl engagement with the hub bi?` means of a lever 3l and associated mechanism II. The contact surfaces may be formed with a suitable lining whereby eilective braking of the member I is obtained.

It will now be appreciated that I have providedV a wing with two types 'of wing sections, so arranged as to increase the starting torgue around its yaw axis. The wing is free to rotate about its axis and the provision of 'differently pitched exdrag at small angles of attack, but a dinerent lift or drag for corresponding sides so as to produce additional torque' for auto rotation of the entire wing. Byjmeans of the present arrangement, an airfoil which comprisesthe main aerodynamic sustenationsurface, may be used as a safety device, since it is designed for free rotation during Hight While I have shown and described the preferred embodiment of my invention, I wish it to be umier-` 'l tensions gives the usual equal or normal lift and stood that I do not coniinemyself to the precise details of construction herein set forth. by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims. ,f

What is claimed is:

1. In an airplane, a freely rotatable wing member comprising two airfoils xedly mounted on the opposite sides of the axis of rotation, one of said airfoils having a positive angle of incidence, the other of said airfoils having a negative angle of incidence.

2. In an airplane, a freely rotatable wing member comprising two airfoils fixedly mounted on the opposite sides of the axis of rotation, one of said airfoils having a positive angle of incidence, the other of said airfoils having a negative angle of incidence, both of said airfoils being tilted upwardly to form a dihedral angle.

3. An airplane wing formed of two airfoils fixedly mounted on opposite sides of the axis vof rotation, one of said airfoils having a positive angle of incidence, and provided with a blunt trailing edge, the other of said airfoils having sharp trailing edge, both of said airfoils beingv double cambered and tilted upwardly to form a dihedral angle. A

5. In an airplane, a freely rotatable wing which comprises the main aero-dynamic sustenation surface, said wing comprising two airfoils xedly mounted on opposite sides of the axis of rotation,

one of said airfoils having a positive angle of incidence, the other of said airfoils having a negative angle of incidence, and means to release said airfoil for free rotation during flight.

6. In an airplane, a plurality of airfoils which comprise the main aero-dynamic sustenation surfaces, one of said airfoils being adapted for ro-I tation and comprising two wing members fixedly mounted on opposite sides of the axis of rotation, one of said wing members having a positive angle of incidence, the other of said wing members having a negative angle of incidence and means to release the rotatable airfoil for free'rotation during flight.

7. In an airplane. two airfoils which comprise the main aero-dynamic sustenation surfaces, one of said airfoils being adapted for rotation, comprising two wing members xedly mounted on opposite sides of the axis of rotation, vone of said 'airfoils having a positive angle of incidence and the main aero-dynamic sustenation surfaces, one

of said airfoils being mounted forwardly of the other and adapted for rotation, said airfoil comprising two wing members xedly mounted on opposite sides of the axis of rotation, one of said airfoils having a positive angle of incidence, the otherA of said airfoils having a negative angle of incidence and means to release the rotatable airfoil for free'rotation during flight.

9. In combination with an airplane having a fixed wing, a safety device comprising a freely rotatable airfoil which normally comprises one of the main aero-dynamic sustenation surfaces, said airfoil being mounted forwardly and above the fixed wing and comprising two wing members fixedly mounted on opposite sides of the axis of rotation, one of said wing members having a positive angle of incidence, the other of said wings having a negative angle of incidence and means to release said airfoil for free rotation dur- 'ing flight.

10. In combination with an airplane having a fixed Wing, a safety device comprising a freely rotatable airfoil which normally comprises one of the aero-dynamic sustenation surfaces, mounted forwardly and above the fixed wing, said airfoil comprising two wing members xedly mounted. on opposite sides of the axis of rotation, one of said wing members having a positive angle of incidence and provided with a blunt trailing edge, the other of said wing members having a negative angleof incidence and provided with a sharp trailing edge and means to release said airfoil for free rotation during flight.

WILBUR E. LIE'I'HV'IN. 

